Position a rack in the middle of the oven. Preheat the oven to 165ºC/325ºF.Line 2 baking sheets with parchment paper.

Put the dark chocolate in a heatproof container or the top of a double boiler and place it over, but not touching, a saucepan of barely simmering water (or the bottom of the double boiler). Stir the chocolate until melted and smooth. Remove from the water and set aside.

Sift the flour, cocoa powder, baking soda and salt into a medium bowl and set aside. In a large bowl, using an electric mixer on medium speed beat the butter, brown sugar and sugar until smoothly blended, about 1 minute.Stop the mixer and scrape the sides of the bowl as needed during mixing. On low speed, mix in the melted chocolate until blended. Add the egg and vanilla, mixing until blended, about 1 minute. Add the flour mixture, mixing just until it is incorporated. Mix in the chocolate chips (both semisweet and white).

Bake the cookies one sheet at a time until they crack slightly on top and a toothpick inserted in the center of a cookie comes out with moist crumbs, not wet batter, about 18 minutes (if the toothpick penetrates a chocolate chip, test another spot).Cool the cookies on the baking sheet for 5 minutes, then use a wide metal spatula to transfer them to a wire rack to cool completely. The outsides of the cookies will become crisp as the cookies cool.

The cookies can be stored in a tightly covered container at room temperature for up to 4 days.

Thanks, the English version looked like a different recipe, but I realized it was just written a little differently. These just came out of the oven, they are fabulous! Great rich chocolate flavor, nice texture, great taste! After baking about 20 dozen cookies I realized I needed a good chocolate cookie and these fit the bill! They are now on my top ten list! MAKE THESE!!

Your chocolate cookies are very nice~ And I like the Nigella Lawson: Chocolate Chip Cookies（http://www.youtube.com/watch?v=f-GROUFa9u8&feature=related），I hope to made this on tomorrow *:人:* ～ Please best wishes for me can succeed made it~ >""",<